1. Field of the Invention
The present invention relates to a head protecting airbag apparatus that is mounted on a vehicle, and inflates an airbag that protects the head of an occupant upon the lateral collision of the vehicle. An airbag deploys and inflates downward from a region at an upper edge of a window of a vehicle so as to cover the interior of the window. Particularly, in the invention, the airbag includes a front window shielding inflatable portion for protecting the head of an occupant who has sit down on a front seat.
2. Background Art
In the related art, in a head protecting airbag apparatus, as described in JP-A-2011-1042, the airbag deploys and inflates downward from a region at an upper edge of a window of vehicle so as to cover the interior of the window upon the inflow of inflation gas. This airbag is folded and housed at the upper edge of the window so that a lower edge of the airbag in a flatly deployed state approaches an upper edge thereof. Additionally, this airbag includes a gas inflow portion and a gas non-inflow portion. The gas inflow portion swells so as to allow inflation gas to flow thereinto and separate an interior wall portion and an exterior wall portion. The gas non-inflow portion is configured to couple the interior wall portion and the exterior wall portion together, and inhibits inflation gas from flowing thereinto.
The gas inflow portion includes a window shielding inflatable portion, a gas supply passage, and a joint port. The window shielding inflatable portion protects the head of an occupant who has sit down, and includes a front window shielding inflatable portion and a rear window shielding inflatable portion. The front window shielding inflatable portion deploys and inflates so as to cover a window at a front seat so as to be able to protect the head of an occupant who has sit down on the front seat of a vehicle. The rear window shielding inflatable portion deploys and inflates so as to cover a window at a rear seat so as to be able to protect the head of an occupant who has sit down on the rear seat of the vehicle. The gas supply passage is arranged along a longitudinal direction at the upper edge of the airbag, and allows both longitudinal ends thereof to communicate with upper ends of the front window shielding inflatable portion and the rear window shielding inflatable portion. The gas supply passage communicates with a tubular joint port that extends upward at the upper edge of the airbag. An inflator that supplies inflation gas is connected to the joint port.
The gas non-flow portion includes a peripheral edge portion that surrounds the gas inflow portion, and a closing portion that extends from the peripheral edge portion and partitions the window shielding inflatable portion.
In the airbag of the related art, a circular closing portion is disposed in the region of the front window shielding inflatable portion. This closing portion is located in front of the gas supply passage, and is disposed so as to be separated from the upper edge of the peripheral edge portion and enter the region of the front window shielding inflatable portion.
Additionally, in the head protecting airbag apparatus of the related art, as shown in JP-A-2001-88651, the airbag is configured so that forwardly descending linear closing portions are vertically juxtaposed in the region of the front window shielding inflatable portion. In this airbag, the inflation gas from the inflator can be rapidly supplied toward the front edge of the front window shielding inflatable portion by the upper and down linear closing portions.
However, in the airbag of the former airbag apparatus, the circular closing portion is disposed apart from the periphery in front of the gas supply passage. Therefore, when the inflation gas from the inflator enters the front window shielding inflation through the gas supply passage, the inflation gas hits the circular closing portion and the inflation gas are branched up and down. As a result, in the former airbag apparatus, the front window shielding inflatable portion is hard to deploy and inflate downward rapidly.
Additionally, in the airbag of the latter airbag apparatus, upon the inflow of inflation gas, the inflation gas is directed to a vertical intermediate portion at a front edge of the front window shielding inflatable portion by the two upper and lower closing portions that extend in a forward downward direction. Therefore, the front window shielding inflatable portion is apt to deploy and inflate downward. However, the two upper and lower closing portions are disposed at the vertical intermediate portion in the region of the front window shielding inflatable portion so as to extend in an oblique direction in the longitudinal direction. These two closing portions are gas non-flow portions that do not swell. Therefore, in this airbag, there is a problem with receiving the head of an occupant at a front seat with sufficient cushioning properties. That is, if the heights of heads are different due to a difference between the physiques of occupants who sit down at a front seat, there is a concern that the center of gravity of a head is disposed at the position of a closing portion with low cushioning properties, which is not preferable.